Mixing tube structure for use in gas ranges



May 31, 1966 N. HUGHES MIXING TUBE STRUCTURE FOR USE IN GAS RANGES Filed May 29, 1964 INVENTQR. HUGHES Nansen-r oo o o 05 06%- a h. J I I g I ll... v

ATTORNEYS United States Patent 3,253,642 MIXING TUBE STRUCTURE FOR USE IN GAS RANGES Norbert Hughes, Lathrup Village, Mich., assignor to Lin-- In a conventional domestic type gas range, fuel gas is furnished to a burner from a valve through a Venturied mixing tube. A jet of fuel gas issuing from the valve inspires primary air into the mixing tube through openings provided for that purpose. The fuel gas and primary air are mixed in the mixing tube for delivery to the burner.

The conventional mixing tube is provided at its upstream end portion with a shutter by which the amount of primary air entering the mixing tube is regulated according to the type of fuel gas being used. The shutter element is also frequently used to provide the mechanical connection between the mixing tube and a hood on the gas valve which contains an orifice from which gas issues into the mixing tube.

Some ranges are designed for use with only one type of fuel gas such as a bottled gas. An example of such a range in a camp cookstove. In such ranges, the shutter arrangement adds unnecessarily to the cost of the mixing tube and furthermore leaves much to be desired with respect to uniformity of the fuel mixture delivered to the burner.

The object of the present invention is to provide a simple, inexpensive mixing tube structure improved to deliver a more uniform fuel mixture to the burner of a gas range designed for use with a specific type of fuel gas.

Generally, the invention is carried out by providing the upstream end portion of the mixing tube with a plurality of struck-in tabs which engage and center the gas valve hood within the mixing tube. The openings left by the tabs provide primary air inlets, and the tabs themselves provide vanes which channel primary air entering the mixing tube in an axial direction. The vanes and primary air inlets are arranged to provide uniform circumferential distribution of the primary air relative to the gas jet.

One form of the invention is illustrated in the accompanying drawings.

FIG. 1 is in general a side elevation of portions of a gas range utilizing the mixing tube structure of the present invention.

FIG. 2 is an enlarged generally sectional view on line 2-2 of FIG. 1.

FIG. 3 is a generally sectional view on line 3-3 of FIG. 2.

Shown in the drawings is a gas range having a cabinet 12 within which is mounted a burner 14 having a base 16 and a ported burner top 18. A valve 20 mounted within cabinet 12 has an outwardly projecting operating stem 22 equipped with an operating handle 24. Valve 20 has an inlet nipple 26 threaded for engagement with a fuel gas supply line 28. Valve 20 has an outlet nipple 30 to which is threaded a hood 32 having an orifice 34- at its downstream end. Hood 32 has an enlargement 36 with wrench flats as shown to facilitate adjustable threading of the hood onto nipple 30.

A mixing tube 38 has adjacent its downstream end 40 a plate 42 sealingly attached to a plate 44 on burner base 16 by bolting as shown. Intermediate portion 46 of the mixing tube has a Venturi configuration. The upstream end portion 48 of the mixing tube has a generally cylindrical wall 50, the diameter of which is greater than that of hood 32.

The mixing tube has an upstream extremity 52, and wall 50 adjacent this extremity is divided into three circumferential segments 50a, 50b, and 50c. Each of these segments continues in a tab 54 which projects toward the interior of the mixing tube. The junctures 56 between the wall segments and tabs are spaced from the adjacent segments to provide three circumferentially spaced primary air openings 58. In the form of the invention illustrated, tabs 54 comprise portions of tube wall 50 which are struck or formed inwardly. Openings 58 are dimensioned to insure a proper supply of primary air for burner 14 using a known type of fuel gas.

Tabs 54 cooperate to define a socket 60 which is engageable in a tight sliding fit around hood 32.. In the form of the invention illustrated, the radially inwardly disposed edge faces 62 of tabs 54 provide this socket. Socket 6!) extends axially over a major portion of the longitudinal extent of hood 32, thereby providing a laterally substantially rigid mechanical connection between valve 20 and mixing tube 38.

In use, tabs 54 substantially center hood 32 and orifice 34 within upstream end 48 of the mixing tube. When valve 20 is opened, a jet of fuel gas issues from orifice 34 into upstream end 48 of the mixing tube and primary air is inspirated into the mixing tube both through openings 58 and the open upstream extremity 52 of the mixing tube. Openings 58 are uniformly spaced around the circumference of the mixing tube and thus primary air is delivered to Venturi 46 in circumferentially uniform distribution around the jet of fuel gas. Moreover, tabs 54 which extend axially of the mixing tube provide vanes which channel the inspired primary air in an axial direction, thereby further improving the uniformity of primary air distribution to the Venturi. Thus, when the fuel gas and primary air are mixed in the mixing tube, the resulting fuel mixture delivered to burner 14 is very uniform.

Mixing tube 38 is assembled to valve 20 by slidably inserting hood 32 into socket 69. Should hood 32 inad vertently be inserted so far into the socket that enlargement 36 abuts and obstructs the flow of primary air into upstream end 52, openings 58 still provide adequate, uniformly distributed primary air to the mixing tube interior.

I claim:

1. In a Venturi-forming mixing tube having a primary air opening and being adapted to be mounted in fuelfurnishing relation between a gas range burner and a gas control valve having a hood with a fuel gas orifice, improved mixing tube structure wherein,

said mixing tube has an end portion the diameter of which is greater than the diameter of said hood of a valve with which said mixing tube is adapted to be used, said end portion having at least three cir cumferential segments,

each of said segments continuing in a tab which extends toward the interior of said end portion,

each segment and its respective tab having a juncture which is spaced circumferentially from the adjacent segment, the circumferential spaces providing primary air inlet openings into said mixing tube, said tabs having portions disposed at circumferentially spaced locations within said end portion of said mixing tube and having axially extending inner edges,

said tab portions being relatively radially located so that said inner edges thereof cooperate to define a socket adapted to receive in close-fitting engagement the hood of a valve with which said mixing tube is adapted to be used.

2. The improved structure defined in claim 1 wherein said socket has an axial extent such that it is adapted to engage said hood at longitudinally spaced locations 3 and thereby provide a laterally substantially rigid conneetion between said mixing tube and hood.

3. The improved structure defined in claim 1 wherein said tabs extend substantially axially of said end portion of said mixing tube and provide vanes which channel primary air entering said tube in a generally axial direction.

4. The improved structure defined in claim 1 wherein said primary air inlet openings are spaced substantially equally around the circumference of said end portion of said mixing tube.

5. In a Ventu-ri forming mixing tube having a primary air opening and being adapted to be mounted in fuelfurnishing relation between a gas range burner and a gas control valve having a hood with a fuel gas orifice, im proved mixing tube structure wherein, said mixing tube has an open end portion the diameter of which is greater than the diameter of said hood of a valve with which said mixing tube is adapted to be used, said end portion having a circumferential wall with at least three circumferentially spaced discontinuities, said end portion having wall portions adjacent said discontinuities which are formed inwardly of said end portion of said tube to provide primary air openmgs, said inwardly formed portions cooperating to define a socket adapted to receive in close-fitting engagement i said hood of a valve with which said mixing tube is adapted to be used,

said socket having an axial extent adequate to provide a laterally substantially rigid connection between said mixing tube and hood,

said inwardly formed wall portions extending substantially axially of said end portions of said mixing tube and thereby providing vanes which channel primary air entering said mixing tube in a generally axial direction.

6. The improved structure defined in claim 5 wherein said openings and vanes are spaced substantially equally ci-rcumferentially of said end portion of said mixing tube so that primary air entering the same is channeled circumferentially uniformly with respect to a jet of fuel gas issuing into said end portion.

References Cited by the Examiner UNITED STATES PATENTS 493,856 3/1893 Bennett. 2,444,142 6/1948 Mueller 1581 15 FOREIGN PATENTS 9,313 3/ 1898 Great Britain.

JAMES W. WESTHAVER, Primary Examiner. 

1. IN A VENTURI-FORMING MIXING TUBE HAVING A PRIMARY AIR OPENING AND BEING ADAPTED TO BE MOUNTED IN FUELFURNISHING RELATION BETWEEN A GAS RANGE BURNER AND A GAS CONTROL VALVE HAVING A HOOD WITH A FUEL GAS ORIFICE, IMPROVED MIXING TUBE STRUCTURE WHEREIN, SAID MIXING TUBE HAS AN END PORTION THE DIAMETER OF WHICH IS GREATER THAN THE DIAMETER OF SAID HOOD OF A VALVE WITH WHICH SAID MIXING TUBE IS ADAPTED TO BE USED, SAID END PORTION HAVING AT LEAST THREE CIRCUMFERENTIAL SEGMENTS, EACH OF SAID SEGMENTS CONTINUING IN A TAB WHICH EXTENDS TOWARD THE INTERIOR OF SAID END PORTION, EACH SEGMENT AND ITS RESPECTIVE TAB HAVING A JUNCTURE WHICH IS SPACED CIRCUMFERENTIALLY FROM THE ADJACENT SEGMENT, THE CIRCUMFERENTIAL SPACES PROVIDING PRIMARY AIR INLET OPENINGS INTO SAID MIXING TUBE, SAID TABS HAVING PORTIONS DISPOSED AT CIRCUMFERENTIALLY SPACED LOCATIONS WITHIN SAID END PORTION OF SAID MIXING TUBE AND HAVING AXIALLY EXTENDING INNER EDGES, SAID TAB PORTIONS BEING RELATIVELY RADIALLY LOCATED SO THAT SAID INNER EDGES THEREOF COOPERATE TO DEFINE A SOCKET ADAPTED TO RECEIVE IN CLOSE-FITTING ENGAGEMENT THE HOOD OF A VALVE WITH WHICH SAID MIXING TUBE IS ADAPTED TO BE USED. 